1. Field of the Invention
The present invention relates to an apparatus and a method for setting degrees of importance to respective categories obtained by hierarchical classification of a plurality of images and to a program for causing a computer to execute the importance degree setting method.
The present invention also relates to an apparatus and a method for selecting a representative image from a plurality of images, and to a program for causing a computer to execute the representative image selection method.
In addition, the present invention relates to an apparatus and a method for selecting an image whose printing is recommended from a plurality of images, and to a program for causing a computer to execute the printing-recommended image selection method.
2. Description of the Related Art
Following the spread of digital cameras and scanners, anyone can obtain digital images with ease. Images are input to personal computers for classification thereof, and the images are often classified into events related to a user. For example, in the case of a trip to Europe, images are firstly classified into categories of countries such as France, UK, and Spain, and images classified into the category of France are further classified into detailed categories of places such as Paris and Nice. Images classified into the category of Paris are then classified into more detailed categories such as the Eiffel Tower, the Arch of Triumph, and the Notre Dame Cathedral. Images of Notre Dame Cathedral may further be classified into much more detailed categories such as “In Front Of The Cathedral”, “Outside The Cathedral”, and “Inside The Cathedral”.
If images are hierarchically classified into a plurality of categories, the images can be referred to later according to events and can be organized with ease.
On the other hand, a user needs to carry out hierarchical classification of the images while viewing the images and refreshing his/her memory, which is a troublesome operation for the user.
For this reason, various methods have been proposed for automatically classifying images. For example, in a method proposed in Japanese Unexamined Patent Publication No. 2000-112997, images are classified into categories based on information on time and date of photography added to the images. In this method, the images are arranged along a time axis based on the information, and the images are classified according to a difference in the time and date of photography between two of the images neighboring each other in the time axis. In another method proposed in Japanese Unexamined Patent Publication No. 2003-108973, images are classified into categories according to the schedule of a user, with reference to schedule information of the user. Furthermore, in a method proposed in U.S. Pat. No. 6,907,141, characteristic quantities are calculated from a plurality of images, and the images are classified into categories based on the relationship between the characteristic quantities of the images.
By using such a method at the time of organizing images, a user does not need to classify images by himself/herself, which reduces the burden on him/her.
Furthermore, if representative images are displayed at the time of organizing images for representing image groups classified into respective categories, what types of images are classified into the respective categories can be easily understood at a glance. For this reason, a method has been proposed for displaying representative images for respective categories at the time of image search (see Japanese Unexamined Patent Publication No. 5(1993)-128166). In addition, a method of displaying representative images in folders corresponding to respective categories has also been proposed (Japanese Unexamined Patent Publication No. 2003-296165).
In the methods described in Japanese Unexamined Patent Publications Nos. 5(1993)-128166 and 2003-296165, representative images are selected by a user. However, methods for automatically selecting representative images have also been proposed. For example, in a method proposed in Japanese Unexamined Patent Publication No. 2000-244849, an image having the largest number of pixels is selected as a representative image. Furthermore, in a method proposed in U.S. Patent Application Publication No. 20030169288, reproduction time of each image is recorded, and an image having a long reproduction time is selected as a representative image.
Meanwhile, a user can store a large number of images in a recording medium, thanks to the spread of digital cameras and a soaring increase in capacity of recording media. On the other hand, an operation is necessary for selecting an image to be subjected to processing such as printing from a large amount of images. Therefore, in order to efficiently select an image, a function is desired for screening images according to a condition before a user determines an image to print, or for selecting an image to print according to the preference of a user.
In Japanese Unexamined Patent Publication No. 2002-010179, a method of automatic elimination of an inappropriate image for printing has been proposed based on image lightness, or an acceleration sensor, or an AF evaluation.
Furthermore, in Japanese Unexamined Patent Publication No. 2001-256498, a method has been proposed for classifying images into images suitable for printing and images not suitable for printing at the time of reception of a printing order regarding the images, by analyzing whether each of the images is well focused and whether each of the images has appropriate lightness.
However, in the case where images have been classified automatically as has been described above, a user does not know which of categories has important images for the user unless the user confirms the images classified into the categories.
Furthermore, in the case where photography is carried out by use of a digital camera, the number of pixels is not changed frequently. Consequently, the number of pixels in images obtained by a digital camera often remains constant. In a situation like this, the method described in Japanese Unexamined Patent Publication No. 2000-244849 cannot select a representative image.
Moreover, in the method described in U.S. Patent Application Publication No. 20030169288 for selecting an image having a long reproduction time as a representative image, a user inputs images from a digital camera to a personal computer, and an image, which is frequently reproduced on the personal computer, is selected as a representative image. However, the representative image cannot be selected immediately after the images are input from the digital camera to the personal computer (that is, in a state where none of the images have been reproduced).
The methods described in Japanese Unexamined Patent Publications No. 2002-010179 and 2001-256498 are image selection techniques that pay attention only to image quality and a photography condition. However, an image to print is difficult to select in the same manner as a general user selects an image to print, only by paying attention to image quality and a photography condition. For this reason, automatic image selection according to an intention of a user has not necessarily been realized.